A persistent antimicrobial resistance pattern and limited methicillin-resistance-associated genotype in a short-term Staphylococcus aureus carriage isolated from a student population

Abstract

The aim of the present study was to assess and compare the antimicrobial susceptibility pattern against a panel of antibiotics and molecular and methicillin resistance-associated genotypes of 120 carriage S. aureus isolates previously isolated from a student population at two isolation events within a one-month interval. The antibiotic susceptibility of isolates was determined using the Kirby-Bauer disc-diffusion method (cefoxitin by Etest). The MRSA was screened using polymerase chain reaction for the presence of the mecA gene. The mecA-positive isolates were subjected to staphylococcal cassette chromosome (SCC) mec typing, multilocus sequence typing (MLST) and eBURST analysis. All isolates were characterized for the presence of the Panton-Valentine leukocidin (PVL) gene, an enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) pattern and the spa type. For the two occasions where S. aureus was isolated, the highest frequency of resistance was observed for penicillin (70% and 65%, respectively), with a lower rate against erythromycin and tetracycline (<12%). All isolates were susceptible to ciprofloxacin and gentamycin. As for methicillin resistance, eight isolates had minimum inhibitory concentrations (MIC) of resistant categories, but 10 isolates (8.33%) were positive for the mecA gene. The mecA-positive isolates belonged to SCCmec types I (n=9) and V (n=1). MLST was resolved for only three MRSAs, ST508 (n=1), ST88 (n=1) and ST96 (n=1). The results of the eBURST analysis showed that the MRSA isolates analyzed in the present study were potentially related to MRSA identified in other countries. Approximately half of the persistent S. aureus carriers harbored S. aureus of a similar spa type in the respective individuals during both isolation events. A persistent antimicrobial pattern and limited distinct MRSAs were observed over the short study period. The latter frequently exhibited SCCmec type I, commonly associated with hospital-acquired (HA) characteristics, but further delineation is needed to justify the origins of these bacteria.

Nasal colonisation, antimicrobial susceptibility and genotypic pattern of Staphylococcus aureus among agricultural biotechnology students in Besut, Terengganu, east coast of Malaysia

“…However, in contrast to our findings, recent surveillance of S. aureus nasal carriers among preclinical and clinical medical students in Klang Valley, western Malaysia, detected a lower prevalence of MSSA (14%) with no MRSA isolated . The 15% (18/119) MRSA rate among S. aureus isolates in our study is higher than the 8.3% (10/120) previously reported among health science students in Malaysian universities .…”

“…Commonly, HA‐MRSA strain would harbour SCC mec type I, II or III and does not frequently carry Panton–Valentine leukocidin ( pvl ) gene, whereas CA‐MRSA strain commonly carries SCC mec ‐IV or V and pvl gene . Previous studies in Malaysia from different localities and populations also indicated the presence of SCC mec ‐I and SCC mec ‐III in the nares of health science students living in the vicinity of the hospital and medical community . Among the 18 MRSAs isolated in our study, SCC mec ‐III (44%; 8/18 isolates) was the most common SCC mec type identified.…”

“…Staphylococcus aureus is one of the most commonly studied microorganisms for causing nosocomial, community and livestock‐acquired infections across the globe. It is part of the human normal flora that colonises anterior nares, skin and throat of 20–30% of the human population . Methicillin‐resistant S. aureus (MRSA) is a strain known to be resistant to β‐lactam antibiotics.…”

Characterization of resistance to selected antibiotics and Panton-Valentine leukocidin-positive Staphylococcus aureus in a healthy student population at a Malaysian University

“…Staphylococcus aureus is a Gram positive and coagulase producing bacterium usually1 20-50% of the human population are often colonized with S. aureus. 2,3 Methicillin-resistant S. aureus (MRSA) is one of the major risk pathogens associated with evolution of antimicrobial resistance. Additionally, antibiotics from the macrolide-lincosamide-streptogramin B (MLS B ) family are usually drugs of choice for the treatment of staphylococcal infections.…”

Livestock-Associated Methicillin-Resistant Staphylococcus aureus in Patients Admitted to Kuwait Hospitals in 2016–2017

“…Isolates from this lineage were first detected in Kuwait in 2016 (21 isolates) and then in 2017 (10 isolates). CC96 MRSA isolates are rare in humans with only single isolates reported previously from Russia (Mendes et al, 2012) and Saudi Arabia (Senok et al, 2016;Mat Azis et al, 2017). However, ST96-MSSA is a common pathogen of rabbits, where it causes different infections (Mendes et al, 2012;Viana et al, 2015;Merz et al, 2016;Moreno-Grúa et al, 2018).…”